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<p>我正试图合并两个CSV文件基于每个文件中的特定字段。</p>
<p><strong>文件1.csv</strong></p>
<pre><code>id,attr1,attr2,attr3
1,True,7,"Purple"
2,False,19.8,"Cucumber"
3,False,-0.5,"A string with a comma, because it has one"
4,True,2,"Nope"
5,True,4.0,"Tuesday"
6,False,1,"Failure"
</code></pre>
<p><strong>文件2.csv</strong></p>
<pre><code>id,attr4,attr5,attr6
2,"python",500000.12,False
5,"program",3,True
3,"Another string",-5,False
</code></pre>
<p>这是我正在使用的代码:</p>
<pre><code>import csv
from collections import OrderedDict
with open('file2.csv','r') as f2:
reader = csv.reader(f2)
fields2 = next(reader,None) # Skip headers
dict2 = {row[0]: row[1:] for row in reader}
with open('file1.csv','r') as f1:
reader = csv.reader(f1)
fields1 = next(reader,None) # Skip headers
dict1 = OrderedDict((row[0], row[1:]) for row in reader)
result = OrderedDict()
for d in (dict1, dict2):
for key, value in d.iteritems():
result.setdefault(key, []).extend(value)
with open('merged.csv', 'wb') as f:
w = csv.writer(f)
for key, value in result.iteritems():
w.writerow([key] + value)
</code></pre>
<p>我得到这样的输出,它可以适当地合并,但并非所有行都有相同数量的属性:</p>
<pre><code>1,True,7,Purple
2,False,19.8,Cucumber,python,500000.12,False
3,False,-0.5,"A string with a comma, because it has one",Another string,-5,False
4,True,2,Nope
5,True,4.0,Tuesday,program,3,True
6,False,1,Failure
</code></pre>
<p><code>file2</code>不会为<code>file1</code>中的每个<code>id</code>都有记录。我希望输出在合并文件中有来自<code>file2</code>的空字段。例如,<code>id</code>1如下所示:</p>
<pre><code>1,True,7,Purple,,,
</code></pre>
<p>如何将空字段添加到在<code>file2</code>中没有数据的记录中,以便合并CSV中的所有记录都具有相同数量的属性?</p>